North Korea has dismissed a report by Japanese media that claimed more than 200 people had lost their lives during a cave-in at a North Korean nuclear test site in early September.

Japanese television network Asahi had reported on Tuesday that a tunnel had caved in at the Punggye-ri Nuclear Test Facility, built under Mount Mantap, in northeast North Korea, linking it to a recent nuclear test.

North Korea’s official KCNA news agency on Thursday blasted the Japanese broadcaster for the “false report” and “misinformation,” which it said had been intended to slander the country and its advances in nuclear technology.

The KCNA said the report “clearly proves that the US and the Japanese reactionaries have gone desperate to slander the DPRK (North Korea) politically and morally, now that they find it hard to check the DPRK’s development of a nuclear force through military threat and barbarous sanctions.”

It said the US and its regional allies intended to cause discord among the North Korean nation after the successful testing of a hydrogen bomb.

The hydrogen bomb was tested by North Korea on September 3, and according to assessments made by Japanese experts, it was eight times more powerful than the atomic bomb that the US detonated on Hiroshima in 1945.

Pyongyang is under political and economic pressure to stop its missile and military nuclear programs.

Despite the enormous pressure, however, Pyongyang says it needs to continue and develop its programs as a deterrent against hostility by the US and its regional allies, including South Korea and Japan.

In response to Washington stepping up economic sanctions against the country, Pyongyang has said it is considering testing a hydrogen bomb over the Pacific Ocean.